Originally Posted by T. Deguzman

For the rear it has 12mm hexes. It is compatible with all the usual 12mm hex rear wheels (AE, Kyosho, TLR, PL, JC, AKA, etc.)

For the front the kit includes BOTH 12mm and 9.8mm hexes. The included HB wheels uses the 12mm hex. The included 9.8mm hexes are compatible with the TLR-22 2WD buggy front wheels.

That's not a typo - the offset compatibility is with the 2WD TLR-22 front which PL, JC, and AKA have versions of. The usual 4WD fronts from the major wheel companies can be made to fit but the hex fit will be a little tight and the front total track width will end up a little narrow. for some reason the hex on the TLR-22 is 9.8mm and the rest of 4WD wheels are 9.5mm. Why there's a 0.3mm difference between the 2WD and 4WD i don't know. The wheel offsets are different as well but during the design phase I studied all the available wheels and I preferred the TLR-22 offset.